The present invention relates generally to a connector for an optical fiber cable, and, more particularly, to a ferrule used in an optical connector that mechanically grips an optical fiber without using epoxy or anaerobic adhesives.
Optical fiber connectors and splices are an essential part of optical fiber communications systems. Connectors may be used to join lengths of optical fiber into longer lengths, or to connect optical fiber to active devices such as radiation sources, detectors, repeaters, or to passive devices such as switches or attenuators.
Many prior art connectors use adhesives or epoxies in securing connector components and the optical fiber. For example, a typical connector includes a ferrule piece rigidly attached to a connector body. Adhesive is injected into a longitudinal bore of the ferrule. A cable is received into the connector body with the enclosed fiber projecting along the longitudinal bore of the ferrule. The adhesive wicks and adheres to the fiber, the ferrule, the connector body, and other connector parts to permanently secure the connector components to one another.
There is a growing demand, however, for a fiber optic connector that is simple to install or assemble in a field setting. In particular, there is a growing resistance to the use of epoxies that require special heat-curing ovens to facilitate solidification, and, in general, to the use of chemicals such as anaerobic adhesives.
Those connectors that have minimized or eliminated the use of epoxies, however, have nevertheless suffered from two inherent problems: First, because of the long length of unsupported fiber in the ferrule and the difference in temperature coefficients of expansion for the fiber, connector body, and ferrule, a small relative movement of the fiber with respect to the ferrule endface can occur as a result of temperature cycles. This can result in undesirable transmission variability. To counteract this problem, some prior art connectors allow the fiber to protrude from the ferrule endface. Unfortunately, this can cause the fiber to chip around the edge. Conversely, if the fiber recedes from the ferrule endface due to contraction caused by temperature variations, the transmission quality will be degraded due to Fresnel reflective losses.
Accordingly, what is sought, and what is not believed to be provided by the prior art, is a fiber optic connector that can be easily installed or assembled without the use of epoxies or adhesives, and also provides mechanical support for the fiber within the ferrule to ensure that the fiber does not move relative to the ferrule over time.